I have been wondering, do Boeing widebody aircraft with flip-down LCD monitors exist?

They are rather common on 737NGs, A320s, and some newer 757s, and can also be found on a few Airbus widebodies under the center overhead bins. Most Boeing widebodies I have seen usually have monitors over the aisles, projectors, or PTVs. Some airlines (such as AA's 767s) also have CRT monitors under the center overhead bins. LCDs, however, are almost always fixed over the aisles or are in-seat.

I understand that the flip-down mechanisim may be a service issue, however, they are basically the standard for new narrowbodies. A few Airbus widebodies (such as some of AA's A300s) also have them.

They might be coming to UA's 744s as part of the cabin reconfiguration. I have heard that UA intends to replace the projectors with LCD displays, but I do not know if that means they'll put a 42"+ unit up at the front or if they will add them overhead along the rows like on their A319/A320 planes.

The IFE systems are sourced by the airlines, not Boeing, so Boeing may not be the best source to ask, even though they perform the initial installation if they were ordered with the frame itself.